I would like to inform my customers when I change the ticket's state to "pending". Well, when I press the button "pending" I see that only note-internal is selectable. I've modified the sysconfig so that now the agent can choose from note-internal, note-external, note-report and email-external, and the default type is email-externatl (Ticket -> Frontend::Agent::Ticket::ViewPending)
But when I send the message the customer can only see it in the web page, but no email is sent.
Where am I wrong?

THank you very very much